This invention is in the field of pulling tools. In particular, it is a tool for pulling a cryogenic cooler away from a dewer-detector head. The cooler and the dewer-detector head are assembled as follows: the dewer-detector head is screwed onto one side of a large flange with a circular opening in the center. The cooler includes a smaller flange with the cold finger extending therefrom and with an o-ring in a groove on the surface of this flange. A rubber mastic is applied to the o-ring and the small flange is inserted through the opening in the large flange to seat against the dewer-detector head. The cold finger thus extends into the dewer and is closely surrounded thereby. Set screws are inserted through holes in the small flange and screwed into holes in the dewer and tightened to hold the small flange in place. Finally, a rubber mastic is applied to cover the set screw heads and the back side of the small flange. Since the small flange is essentially potted into the large flange, one normally attempts dissembly by removing the screws holding the dewer-detector head to the large flange and by pulling on the dewer-detector head. Unfortunately, there is very little clearence between the cold finger and the adjacent (glass) wall of the dewer and the slightest rocking motion will cause the cold finger to contact and to break the dewer. Since a dewer is very expensive, this method of disassembly is unacceptable. The instant invention exerts a force to pull the small flange from the opening in the large flange (after the set screws are removed).